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Message: 6978

Author: ian.rushforth

Date: 13/12/2016

Subject: Cell-Graphics Bug

 

I've just noticed this comment on Andrew's MM Room-format webpage, which intrigued me:

There's a similar bug in the Jet Set Willy game-engine, though not identical - try writing "West of Kitchen" or "The Wine Cellar" (Rooms 24 and 49 respectively in the original Jet Set Willy ) in Manic Miner, and you'll see that Manic Miner will corrupt some block-graphics that Jet Set Willy does not!

Surely the basic mechanism behind the bug is the same for both JSW and MM: namely, that the CPIR loop exits too early if it picks up a graphic byte that matches the colour-attribute byte of one of the cell-types?

So, does the difference arise from the order in which the various cell-types are listed within the two game engines? (e.g. Fire is defined before Conveyor in JSW, whereas Fire comes after Conveyor in MM.)

 

 

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